1. Field of the Invention
This invention relates to novel anthranilic acid derivatives exhibiting an extremely strong antiallergic activity when administered orally to mammals including human beings. More particularly, this invention relates to anthranilic acid derivatives inhibiting anaphylaxis caused by an antigen-antibody reaction.
2. Description of the Prior Art
Disodium chromoglicate is well known as the only one drug that inhibits the disruption of mast cells and the liberation therefrom of chemical mediators. However, this compound will lose its pharmacological effect when administered orally, and the extent to which this compound is applicable to naturally limited. Thus, the development of an antiallergic agent which can exhibit a sufficient therapeutic effect by oral administration has long been demanded in the field of medicine.
On the other hand, many compounds which have an N-acylaminobenzoic acid moiety and which might be considered to bear some distant resemblance to the compounds of this invention from the standpoint of chemical structure have been reported e.g., in Japanese Kokai No. 49-9,335, J. Pharmacol., Vol. 58, pages 483-88, Igakunoayumi, Vol. 106, pages 576-85, Liebig's Annalen der Chemie, Vol. 341, pages 471-84, etc. In the above literatures or patents, it has been reported that some compounds, especially N-(3,4-dimethoxycinnamoyl) anthranilic acid, inhibit the disruption of mast cells and the release therefrom of chemical mediators caused by an antigen-antibody reaction and thus possess a strong antiallergic action when administered orally to mammals including human beings. However, such compounds do not have a substituent or substituents on their aromatic rings which contains amino and carboxyl groups. The compounds of this invention have one or more substituents on their aromatic rings which contains amino and carboxyl groups and exhibit a strong antiallergic action when administered orally.